Joined body of piezoelectric single-crystal substrate and support substrate

Abstract

A bonded body includes a supporting substrate; a piezoelectric single crystal substrate composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate; and an amorphous layer present between the supporting substrate and piezoelectric material substrate, and the amorphous layer contains one or more metal atom selected from the group consisting of niobium and tantalum, an atom constituting the supporting substrate and argon atom. A concentration of the argon atom in a central part of the amorphous layer is higher than a concentration of the argon atom in a peripheral part of the amorphous layer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is a continuation of PCT / JP2019 / 004999, filed Feb. 13, 2019, which claims priority to Japanese Application No. JP2018-095260, filed May 17, 2018, the entire contents of which are hereby incorporated by reference.TECHNICAL FIELD[0002]The present invention relates to a bonded body of a piezoelectric single crystal substrate and supporting substrate.BACKGROUND ARTS[0003]It has been widely used an SOI substrate composed of a high resistance Si / SiO2 thin film / Si thin film, for realizing a high-performance semiconductor device. Plasma activation is used for realizing the SOI substrate. This is because the bonding can be realized at a relatively low temperature (400° C.). It is proposed a composite substrate composed of similar Si / SiO2 thin film / piezoelectric thin film for improving the performance of a piezoelectric device (patent document 1). According to patent document 1, the piezoelectric single crystal substrate composed of lithium ni...

AI Technical Summary

Benefits of technology

The technical effect of this patent is to reduce the warping of a bonded body when heated, in a piezoelectric single crystal substrate and supporting substrate. This is achieved by increasing the energy intensity of an argon atomic beam at the central part of the bonding interface, which results in a higher argon concentration at the central part and a thicker amorphous layer. This in-plane distribution of the argon concentration and thickness of the amorphous layer helps to relax the stress applied onto the piezoelectric single crystal and suppress the warping of the bonded body upon heating.

Problems solved by technology

Due to an increase of transmitted electric power required by recent increase of communication amount and heat generation from surrounding devices resulting from fabrication into a module, an acoustic wave filter is under the condition susceptible to high temperature.

As a result, the acoustic wave filter composed of the piezoelectric single crystal substrate could not be used for a high-performance communication device.

However, as a high temperature of about 80° C. is applied onto the bonded body of the piezoelectric single crystal substrate and supporting substrate, the warping may occur.

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